Adult females on frozen thawed

So I recently purchased a 1600 gram female pastel, and was asked if I would take a 2100 gram female normal ”which I happily agreed too” both of them readily take frozen thawed, but I noticed they first meal the take off the tongs they strike, but the second and third ”i have been testing out smaller meals with multiple offerings lately weight between 31 and 37 gram weaned rats.” they do not strike just find the head and open their mouths and gently take the rat off my tongs and start eating instantly like they know they rat isn't alive and there is no need to constrict, where as before offering one larger meal to each girl they would strike and constrict for a few minutes fill they believed the rat was dead. Has anybody else noticed older animals displaying similar behavior, just found it strange that two breeder adults displayed similar traits at roughly the same time. And considering the female normal 2100 grams was only being fed alive mice said the lady who gave her to me, trying to see if maybe anybody else has had a similar experience and if that frozen thawed eaters can distinguish between the two. Just a random thought I has while feeding my collection right now.

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Ugh auto correct on my phone, sorry for the misspelled words.

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